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Li D, Sun S, Xiao Z, Song J, Shao DF, Tsymbal EY, Ducharme S, Hong X. Giant Transport Anisotropy in ReS_{2} Revealed via Nanoscale Conducting-Path Control. PHYSICAL REVIEW LETTERS 2021; 127:136803. [PMID: 34623838 DOI: 10.1103/physrevlett.127.136803] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/28/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
The low in-plane symmetry in layered 1T'-ReS_{2} results in strong band anisotropy, while its manifestation in the electronic properties is challenging to resolve due to the lack of effective approaches for controlling the local current path. In this work, we reveal the giant transport anisotropy in monolayer to four-layer ReS_{2} by creating directional conducting paths via nanoscale ferroelectric control. By reversing the polarization of a ferroelectric polymer top layer, we induce a conductivity switching ratio of >1.5×10^{8} in the ReS_{2} channel at 300 K. Characterizing the domain-defined conducting nanowires in an insulating background shows that the conductivity ratio between the directions along and perpendicular to the Re chain can exceed 5.5×10^{4} in monolayer ReS_{2}. Theoretical modeling points to the band origin of the transport anomaly and further reveals the emergence of a flat band in few-layer ReS_{2}. Our work paves the path for implementing highly anisotropic 2D materials for designing novel collective phenomena and electron lensing applications.
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Affiliation(s)
- Dawei Li
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Shuo Sun
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Zhiyong Xiao
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Jingfeng Song
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Ding-Fu Shao
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Stephen Ducharme
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
| | - Xia Hong
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, USA
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Sim S, Lee D, Lee J, Bae H, Noh M, Cha S, Jo MH, Lee K, Choi H. Light Polarization-Controlled Conversion of Ultrafast Coherent-Incoherent Exciton Dynamics in Few-Layer ReS 2. NANO LETTERS 2019; 19:7464-7469. [PMID: 31448923 DOI: 10.1021/acs.nanolett.9b03173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Coherent light-matter interaction can transiently modulate the quantum states of matter under nonresonant laser excitation. This phenomenon, called the optical Stark effect, is one of the promising candidates for realizing ultrafast optical switches. However, the ultrafast modulations induced by the coherent light-matter interactions usually involve unwanted incoherent responses, significantly reducing the overall operation speed. Here, by using ultrafast pump-probe spectroscopy, we suppress the incoherent response and modulate the coherent-to-incoherent ratio in the two-dimensional semiconductor ReS2. We selectively convert the coherent and incoherent responses of an anisotropic exciton state by solely using photon polarizations, improving the control ratio by 3 orders of magnitude. The efficient modulation was enabled by transient superpositions of differential spectra from two nondegenerate exciton states due to the light polarization dependencies. This work provides a valuable contribution toward realizing ideal ultrafast optical switches.
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Affiliation(s)
- Sangwan Sim
- Division of Electrical Engineering , Hanyang University , Ansan 15588 , Korea
| | - Doeon Lee
- Department of Electrical and Computer Engineering , University of Virginia , Charlottesville , Virginia 22903 , United States
| | - Jekwan Lee
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Korea
| | - Hyemin Bae
- School of Electrical and Electronic Engineering , Yonsei University , Seoul 03722 , Korea
| | - Minji Noh
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Korea
| | - Soonyoung Cha
- Center for Artificial Low Dimensional Electronic Systems , Institute for Basic Science (IBS) , Pohang 3767 , Korea
| | - Moon-Ho Jo
- Center for Artificial Low Dimensional Electronic Systems , Institute for Basic Science (IBS) , Pohang 3767 , Korea
- Department of Materials Science and Engineering , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Korea
| | - Kyusang Lee
- Department of Electrical and Computer Engineering , University of Virginia , Charlottesville , Virginia 22903 , United States
- Departments of Materials Science and Engineering , University of Virginia , Charlottesville , Virginia 22903 , United States
| | - Hyunyong Choi
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Korea
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